Hello,

according to my personal experience, I may recommend RNA Later (https://www.thermofisher.com/cz/en/home/brands/product-brand/rnalater.html). Not too expensive (about 200 dollars) and you can store your sampled tissue in it for several years at -20 °C.

Hope this help

Neither answer is helpful.1. Farmers solution is a standard fixative prior to preparing PEN membrane paraffin slides for laser micro-dissection-homogeneous cell areas are removed for RNA extraction (with no RNA degradation) then RNA sequencing for transcriptomic analysis-this has been done for years. I wish to know how long the tissue can stay in the fixative - probably months? 2. RNA later solution is simply sulphate salts that precipitate and unwind the RNAase protein-it is not a preservative (i.e. kills pathogens) or a fixative and does not preserve tissue, only 'protects' RNA. The tissue undergoes necrosis with all histology lost-but RNA is still there if the sample was stored in very cold conditions.

Again all these answers are unhelpful. I am not interested in methods to preserve RNA, which include: Fresh samples dissected on dry ice then placed in OCT then sliced with a cryostat; crushing in liquid nitrogen; storing in RNA later (sulphate salts)- are all standard, well known methods. Placing samples in a coagulative fixative such as Farmers Solution (75% ethanol +25% glacial acetic acid) is also standard method to preserve tissue and nucleic acids . The question is-how long can a sample be left in Farmers solution before the RNA is lost?